Among its conditions is the congregation, and they differed in the amount of the congregation. Some say one with the imam, and by that I say, “Present and travel with me,” and some say two other than the imam, and some say three rather than the imam, and some say forty, and some say thirty, and some say twelve, and some do not stipulate a number, but believe that it is permissible. If it is less than forty, it is not permissible to do three or four. This condition is one of the conditions of obligation and validity, meaning that Friday is obligatory and valid.